This invention relates generally to pump assemblies, and more particularly, to multistage end-suction pump assemblies.
Pump assemblies are provided within pipe systems of residential, commercial or industrial facilities for increasing the pressure and flow of the fluid within the pipe system. The pump assembly is usually fitted to the pipe system to circulate the fluid under pressure. The typical pump assembly has an inlet that supplies fluid to the pump through a manifold having an impeller chamber, an impeller located in the chamber, a power head (e.g. motor and shaft) to drive the impeller, and an outlet that returns the fluid to the pipe system. The inlet is fitted to a supply pipe and the outlet is fitted to a discharge pipe. The size of the pump assembly is selected based on the particular pipe system and the desired pressure and flow of the fluid within the pipe system. For example, various pump assembly components may be provided to accommodate various sized supply pipes and discharge pipes, which are typically different than one another. The particular pump assembly components chosen depend on the particular application. In another example, in applications where a high pressure is desired, a pump assembly having a relatively larger motor or a relatively larger impeller may be used. In some known pump assemblies, multiple impellers are used, such as in a multistage pump assembly.
The multistage pump assemblies typically have one of two configurations, namely a horizontal configuration and a vertical configuration. In both configurations, the pump assemblies typically stack the multiple impellers in stages in series. In the horizontal configuration, the stack is oriented generally horizontally when installed; and in the vertical configuration, the stack is oriented generally vertically when installed.
In a typical horizontal configuration, the manifold having the inlet is positioned at one end of the stack and the outlet is positioned within a pump head at the opposite end of the stack. These types of pump assemblies include a motor shaft being supported by a shaft bearing within the motor. The impellers are directly coupled to the motor shaft. A drawback with this type of configuration is the number of stages that may be used is limited, due to the drive capacity of motor and the weight of the shaft and the impellers on the shaft bearing. Additionally, this design is complicated to manufacture and assemble. Additionally, repair and/or replacement of the pump head is difficult and requires that the majority of the pump assembly (e.g. the manifold, each stage, and the pump head) be completely disassembled for servicing.
In a typical vertical configuration, the inlet and outlet are both provided in a common manifold and are axially aligned with one another such that the pump assembly is fit within a line of the pipe system. The in-line orientation of the inlet and outlet is limited to particular applications that allow for in-line connection to the standard pipe system. A problem encountered with this type of connection occurs in installing the pump assembly into an existing pipe system, particularly in retro-fitting, replacing or upgrading an existing system with a new pump assembly. The existing pipe system may not allow for an in-line connection. As such, these types of pump assemblies are not suitable for all applications.